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Date published: April 1, 2015
Of every three American adults, one is obese, one is overweight, and only one is lean. And all of us are at risk for gaining more.
From the latest “you’ll never be hungry” diet to that “weird tip to lose belly fat,” most dieting myths focus on how to lose weight. Yet myths, misunderstandings, and excuses also explain how we got that spare tire in the first place.
If we knew more about what happens to the excess calories we eat-and how hard it may be to lose them for good-maybe we’d think twice before we reach for that extra slice of pizza or cheesecake.
It’s no secret that losing weight-and keeping it off-is tough. That’s all the more reason to avoid moving up a pants size in the first place. Here we correct 8 common misconceptions to help you play defense in the battle of the bulge.
1 I can lose it later.
Let’s say you’ve been on vacation. Or it’s the holidays. You know you’ve put on a few pounds, but so what? You’ll just cut back when things get back to normal, and your waist will shrink back to its pre-vacation or preholiday size in a few weeks, right?
Not so fast.
“A student of mine was interested in how long it would take somebody to lose the weight they had gained from holiday overeating if all they did was go back to their regular pre-Thanksgiving diet,” says Kevin Hall, senior investigator in the Laboratory of Biological Modeling at the National Institute of Diabetes and Digestive and Kidney Diseases.
“The funny thing was that they wouldn’t have lost all the new weight by the time the next holiday period came around.”
So just several weeks’ worth of indulgence can have lasting consequences.
“If you never quite lose the weight that you gained the previous year, you’re just ratcheting your weight up year after year after year,” explains Hall.
Why does it take so long to lose those extra pounds that you put on so quickly? The old rule of thumb-that you can expect to lose a pound for every 3,500 calories you cut-is wrong for several reasons.’2
You’ve lost muscle. The 3,500calorie rule assumes that you’ve lost only fat. In fact, about 25 percent of the weight that dieters lose is lean tissue.
“Most of the lean body mass is skeletal muscle,” says Hall. “And even at rest, it burns more calories than fat tissue.”
* Your organs are smaller. “As you lose weight, your liver, kidneys, and other organs shrink,” says Hall. “So the number of calories that are required to keep those organs operating goes down.”
Roughly 60 to 70 percent of your calories are used just to keep your heart beating, your kidneys filtering blood, etc., 24 hours a day.
“The liver and kidneys are much smaller than the sum total of your skeletal muscles,” explains Hall. “But per unit weight, they are 10 to 20 times more active than skeletal muscle at rest. So even small changes in these organs can make relatively substantial changes in metabolic rate.”
* Exercise burns fewer calories. As your body becomes smaller, moving it around becomes easier. Going for a walk or climbing the stairs burns fewer calories than it used to.
* Your metabolism is slower. Your metabolism slows down when you cut calories,” says Hall. It’s as though your body is hunkering down to face scarcity, so it burns fewer calories per minute.
“We’ve actually measured contestants on the television show ‘The Biggest Loser,'” says Hall. “These folks were doing a lot of exercise, so they were preserving their lean tissue as much as possible.” (Only 18 percent of their lost weight was lean tissue.) But their metabolic rate still fell by an average of about 800 calories per day.3
“You could explain only about 300 of the 800 calories by their smaller size,” notes Hall. The remaining 500 calories were due to slower metabolism.
“Now, their case is an extreme,” he adds. But even if you went from, say, 165 pounds to 145 pounds, you would have to eat fewer calories than you ate before you first gained those 20 pounds.
“Once you lose at least 10 percent of your weight and your weight is stable, you may need to eat 10 to 15 percent fewer calories to keep the weight off,” says Hall. That’s because your body burns fewer calories both at rest and when you move.4
Hall and his colleagues have created an online body weight calculator that considers all those changes to estimate how long it will take you to lose, say, 20 pounds.
“We built our online simulators for people to better understand how changes in diet and physical activity can be traded off to both get to a goal and then maintain that goal permanently,” he explains.
(Go to bwsimulator.niddk.nih.gov or download the free Body Weight Simulator app for the iPhone.)
Bottom line: A slower metabolism and less lean mass make it hard to lose all the extra pounds you gain.
2 Once it’s off, it’ll stay off.
You go on a diet for six months. Gone are those extra 10 or 20 pounds. But slowly, they start to reappear. That’s what happens in most large studies.5 What’s up?
“We’ve looked at body weight changes to figure out what people have done to their food intake, and what we found was pretty surprising,” says Hall.
“Initially, most people go like gangbusters. They’re pretty good about sticking to their weight-loss program for a while.”
But they gradually start to eat more, and they don’t notice because they keep losing weight. That’s because they’re still eating less than when they started dieting. (See “Calories & Pounds: We’re Back!” p. 4.)
“By the time they reach their maximum success, after six to eight months, they’re about 80 percent of the way back to what they were eating at the beginning of the weight-loss program,” says Hall.
“They’re eating, say, 100 calories per day less, whereas they started out probably cutting about 700 calories out of their diet. So 80 percent of that initial diet has been lost.”
And their weight creeps back up.
“We’re working on tools to track peoples’ weight,” says Hall, “so we can provide early warning signs that they’ve started to back off on their original diet.”
Bottom line: Many dieters regain lost weight because they gradually start eating more.
3 Fat is fat, no matter where it is.
When you overeat, your body needs to stash the excess calories somewhere. But your odds of losing those extra pounds-and their impact on your health-depend on where the fat ends up. And much of that is beyond your control (see No. 5).
“We know that if people gain leg fat, they actually gain new fat cells, so they’re sort of stuck with new fat cells,” says Michael Jensen, director of the Obesity Treatment Research Program at the Mayo Clinic in Minnesota.
That’s not true for belly fat.
“At least with modest weight gain, almost all the weight gain in upper body fat is an increase in fat cell size,” says Jensen. “Each fat cell just agrees to store a little bit more. That makes upper body fat easier to lose.”
Jensen and his colleagues fed 23 lean men and women an extra 400 to 1,200 calories a day as ice cream shakes, Snickers bars, and Boost Plus energy drinks.6 After two months, their weight jumped by about eight pounds.
After another two months-during which the participants cut their calories and boosted their exercise-they only lost an average of six pounds. And what remained was mostly extra leg fat.
“When we look at the loss of that gained weight, upper body fat goes away first and leg fat goes away last, because you created a whole new set of cells there,” says Jensen. “Once you have a new fat cell, it’s very ard to get rid of it, so it’s the last place you will lose weight.”
And it’s not just a few cells. In another study, Jensen found that 3% pounds of new leg fat created roughly 2.6 billion new fat cells within two months.7 Sure you need that cupcake?
Of course, those upper body fat cells can’t keep getting bigger and bigger.
“Your fat cells can only get so big,” explains Jensen. “From the smallest fat cell to the biggest fat cell is only about a four-fold increase. And we all know people who have gained more than four times as much fat as they had when they were skinny. So eventually, you have to start recruiting new fat cells.”
Apparently, we all have pre-adipocytes (pre-fat cells) that are just waiting to be pressed into service whenever we need them.
The irony: storing more fat in your legs is actually healthier.
“People who gain predominantly leg fat tend to have a much better metabolic profile than people who put on a lot of abdominal fat,” notes Jensen. “They’re less likely to get diabetes, less likely to get high cholesterol and high triglycerides, and less likely to get hypertension and sleep apnea.
“My biggest worry is when a patient comes in with a big gut and skinny legs,” he adds. “I know they’re probably in trouble.”
It’s not clear why upper body fat-especially the deep-belly visceral fat-is worse. One possibility: visceral fat cells may send more fat to the liver. Or a generous layer of visceral fat may be a sign that your subcutaneous fat is faulty.8
“One speculation is that people gain visceral fat because the subcutaneous fat in their abdomen and thighs is not doing its job,” says Jensen. “Its job is to sequester fat from the excess calories you ate so that it can’t harm your lean tissue.
“And if the subcutaneous fat can’t do its job, the fallback job goes to the visceral fat. And if the visceral fat can’t do its job, the fat starts building up in your liver and muscles and other places where you really, really don’t want it.”
“Those organs can’t package fat in the safe triglyceride form very well,” explains Jensen. “So the fatty acids-the individual components of triglycerides-can interfere with cell function.”
You might end up with non-alcoholic fatty liver disease, for example.
“It’s as though you kept putting gas in the gas tank when it’s full and now it’s running all over the side of your car,” says Jensen. “It’s a bad situation.”
Bottom line: Extra calories can lead to leg fat that’s tough to lose or deep-belly fat that’s a risk to your health.
4 You have to go out of your way to overeat.
You needn’t sit at home all day and stuff your mouth with potato chips, candy bars, and ice cream to end up with a spare tire. You just have to eat-like most of us do- in restaurants, shopping malls, movie theaters, ballparks, airports, drug stores, gas stations, and at virtually every other public place.
“Food is now available everywhere,” says Kevin Hall, of the National Institute of Diabetes and Digestive and Kidney Diseases. “It’s even socially acceptable to eat during meetings. In fact, food is now provided at meetings.”
Where isn’t food available? And the size of meals has grown.
“The restaurant is a toxic environment,” says Susan Roberts, director of the Energy Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. “The portion sizes are enormous, and the calories are excessive.”
In a 2013 study, she and colleagues analyzed the calories in the 42 most frequently eaten meals from independent and smallchain sit-down restaurants in the Boston area. They included popular cuisines like Mexican, American, Chinese, Italian, Japanese, Thai, Indian, Greek, and Vietnamese.
“These establishments make up half of all restaurants but offer no calories or other Nutrition Facts on their menus,” notes Roberts.
The average meal had roughly 1,300 calories-about two-thirds of the calories an average person needs in a day.9
“And people have no idea how many calories they’re eating,” adds Roberts.
Bottom line: What’s typically served in restaurants can make you gain weight.
5 All extra calories are equal.
Can you change where your extra calories end up?
“There’s certainly some genetic component to it,” says Mayo’s Michael Jensen. “Women, because of female hormones, are going to be more able to store leg fat than men.” (That is, until menopause, when they may wonder where that waist went.)
“It turns out that smokers are probably not as good at making new leg fat cells,” he adds. “And people who drink a lot of alcohol tend to store more fat in the abdominal area.”
Saturated fat may also make a beeline to your belly. Swedish scientists added enough 250-calorie muffins-typically three a day-to the diets of 39 young lean adults to make them gain about 3 xh pounds over seven weeks. But those who got muffins made with saturated fat (palm oil) gained more visceral and liver fat than those who got muffins made with a polyunsaturated fat (sunflower oil).10
And it’s not just palm oil. The same researchers found more liver fat when they fed obese people butter instead of sunflower oil. (That study didn’t measure visceral fat.)n
The extra calories from added sugars like sucrose and high-fructose corn syrup may also prefer to settle in deep-belly fat.
When researchers gave 32 overweight or obese middle-aged men and women a high dose of fructose or glucose for 10 weeks, both groups gained about three pounds.12
“But fructose significantly increased visceral fat, while glucose did not,” explains Kimber Stanhope, associate researcher at the University of California, Davis.
(Since we get glucose from nearly all carbs but fructose only from sugars, the only way to limit fructose is to limit added sugars-from soft drinks, frappuccinos, cookies, cakes, ice cream, muffins, doughnuts, scones, candy, and other sweets.)
“A Danish study that gave overweight people a much smaller dose of fructose-a liter of sucrose-sweetened cola per day for six months- also found an increase in visceral fat,” notes Stanhope.13 “More studies are needed, but this direct experimental evidence suggests that sugars may increase visceral fat.”
Bottom line: Excess calories from foods high in sugars or saturated fats may be more likely to settle in deep-belly fat.
6 You can boost your metabolism.
“Metabolism boost,” boasts the label of Organic Matcha green tea powder, which also claims to be a “calorie burner.” “Supports energy and metabolism,” claims Herbalife Herbal Tea Concentrate.
The catch: companies need virtually no evidence to make those claims. “This boosting of metabolism is pretty overblown,” says Tufts’ Susan Roberts.
“Magazines and supplements love to talk about ways to boost your metabolism. But you can eat a brownie with 700 calories in about 10 seconds, and there is nothing that you can remotely do to change your metabolism by anywhere near that much, except to give up your job and spend all your day in the gym.”
Take green tea. Some small studies report that it leads to a bump in metabolic rate, but long-term studies find that it makes little or no difference in weight.14
The largest study: With funding from Coca-Cola, researchers randomly assigned 572 people to a weight-loss program with or without three daily cans of diet cola, each fortified with green tea extract (83 mg of EGCG) and caffeine (100 mg). After three months, the diet-cola drinkers had lost no more weight than the others.15
Does anything help you burn more calories per minute?
“Exercise is going to help a bit because muscle is more metabolically active than fat,” says Roberts. “So if you have five more pounds of muscle and five pounds less fat, it will make a bit of difference, but not a huge difference.
“Weight control is dominated by how many calories you eat. That’s the honest truth.”
Bottom line: Don’t expect to lose much weight from “metabolism boosters.”
7 There’s a magic bullet diet.
The Paleo Diet. The Sugar Impact Diet. The New Atkins Diet. All promise to make the pounds peel away fast.
Most experts wouldn’t agree. In 2013, the Obesity Society, American Heart Association, and American College of Cardiology issued a report on overweight and obesity.5 Its advice: cut calories or try a diet that’s low in fat or carbs or whatever.
“We started off with different, almost religious, beliefs as to what diet would be better,” says the Mayo Clinic’s Michael Jensen. “And we wound up being agnostic.
“We looked for studies that had results for at least a year, and preferably two years, because for most of us who treat patients with obesity, it’s not what they did in six months that matters, it’s what they did in two years that really drives our decision making.”
And those longer trials didn’t reveal any magic bullets. “We found that in the end, on average, the diets produced about the same amount of weight loss,” says Jensen.
The key for weight loss is the long game.
“For any given person, it’s really more a matter of what can they stick with,” notes Jensen, “rather than whether there’s a specific diet that we know is best for them.”
Bottom line: Don’t pin your hopes on the latest “miracle” diet.
8 I can work off the extra calories.
So what if you had General Tso’s chicken or steak fajitas for dinner? So what if you shared a large bucket of popcorn at the movies? You can always work it off, right?
“People totally overestimate how many calories they’ll burn when they exercise,” says Roberts.
“We recently asked people, ‘What do you need to do to lose weight?’ About three-quarters of them said, ‘My trouble is that I stopped going to the gym’ or ‘I’ve been lazy. I need to go to the gym.’ They were beating themselves up because they weren’t doing enough exercise.”
In fact, most studies find that people who are told to cut calories lose more weight than those who are told to exercise more, though a mix of diet plus exercise is best in many studies.16,17
“Exercise for weight loss is often unhelpful,” says Roberts. “Several years ago, a study looked at the individual response to an exercise program. It was terrifying because they found a huge variability.”
UK researchers had 35 overweight or obese men and women exercise (on a stationary bike, treadmill, or stepping or rowing machine) long and hard enough to burn 500 calories per session, five times a week.18
After 12 weeks, the average weight loss was 8 pounds, but some people lost 32 pounds, while others gained 4 pounds. Those who lost the least weight also reported more hunger and ate more on a given day near the end of the study than did those who lost the most weight.
“For some people it was clearly working, but for others it was counterproductive,” says Roberts.
It’s not just individual differences. Other factors, like temperature, might also matter. In a recent study, researchers assigned 16 overweight people to walk for 45 minutes on a treadmill when the room temperature was either 46° or 68° Fahrenheit.19 They ate more calories (1,300) at an all-you-can-eat buffet after walking in the cold temperature than after walking in the typical indoor temperature (1,170 calories).
“You need to keep doing exercise for your health, for preventing disabilities and problems in old age,” says Roberts. “But for most people, exercise is not the solution for losing weight.”
Bottom line: Exercise when you can, but don’t count on it alone to lose-or keep off-extra pounds.